How long is the validity of SMS?

1, the validity of SMS is permanent when the phone is turned on.

2. Mobile phone is turned off: Take China Mobile as an example, the validity period of mobile phone short messages is usually 48 hours; SMS will be stored in the system for 48 hours. If the phone is turned off or stopped, the system will keep the SMS for 48 hours. If you turn on your phone or receive a cell phone signal within 48 hours, the system will push the SMS to your cell phone. If it exceeds 48 hours, it cannot be received after the deadline, and the short message cannot be retrieved.